BookKeeper configuration

A reference guide to all of BookKeeper's configurable parameters

The table below lists parameters that you can set to configure bookies. All configuration takes place in the bk_server.conf file in the bookkeeper-server/conf directory of your BookKeeper installation.

Server parameters

Parameter

Description

Default

bookiePort

The port that the bookie server listens on.

3181

allowMultipleDirsUnderSameDiskPartition

Configure the bookie to allow/disallow multiple ledger/index/journal directories in the same filesystem disk partition

listeningInterface

The network interface that the bookie should listen on. If not set, the bookie will listen on all interfaces.

eth0

advertisedAddress

Configure a specific hostname or IP address that the bookie should use to advertise itself to
clients. If not set, bookie will advertised its own IP address or hostname, depending on the
listeningInterface and useHostNameAsBookieID settings.

eth0

allowLoopback

Whether the bookie is allowed to use a loopback interface as its primary
interface (the interface it uses to establish its identity). By default, loopback interfaces are not allowed as the primary interface.

Using a loopback interface as the primary interface usually indicates a configuration error. It’s fairly common in some VPS setups, for example, to not configure a hostname or to have the hostname resolve to 127.0.0.1. If this is the case, then all bookies in the cluster will establish their identities as 127.0.0.1:3181, and only one will be able to join the cluster. For VPSs configured like this, you should explicitly set the listening interface.

false

useHostNameAsBookieID

Whether the bookie should use its hostname to register with the ZooKeeper coordination service. When false, the bookie will use its IP address for the registration.

false

useShortHostName

Whether the bookie should use short hostname or FQDN hostname for registration and ledger metadata when useHostNameAsBookieID is enabled.

false

allowEphemeralPorts

Whether the bookie is allowed to use an ephemeral port (port 0) as its server port. By default, an ephemeral port is not allowed. Using an ephemeral port as the service port usually indicates a configuration error. However, in unit tests, using an ephemeral port will address port conflict problems and allow running tests in parallel.

false

enableLocalTransport

Whether allow the bookie to listen for BookKeeper clients executed on the local JVM.

false

disableServerSocketBind

Whether allow the bookie to disable bind on network interfaces, this bookie will be available only to BookKeeper clients executed on the local JVM.

false

bookieDeathWatchInterval

Interval to watch whether bookie is dead or not, in milliseconds.

1000

extraServerComponents

Configure a list of extra server components to enable and load on a bookie server. This provides a plugin mechanism to run extra server components along with a bookie server.

Worker thread settings

The number of threads that handle write requests. if zero, writes are handled by Netty threads directly.

1

numReadWorkerThreads

The number of threads that handle read requests. If zero, reads are handled by Netty threads directly.

8

numLongPollWorkerThreads

The number of threads that handle long poll requests. If zero, long poll requests are handled by Netty threads directly.

0

numJournalCallbackThreads

The number of threads that handle journal callbacks. If zero, journal callbacks are executed directly on force write threads.

1

numHighPriorityWorkerThreads

The number of threads that should be used for high priority requests (i.e. recovery reads and adds, and fencing). If zero, reads are handled by Netty threads directly.

8

maxPendingAddRequestsPerThread

If read worker threads are enabled, limit the number of pending requests, to avoid the executor queue to grow indefinitely. If zero or negative, the number of pending requests is unlimited.

10000

maxPendingReadRequestsPerThread

If add worker threads are enabled, limit the number of pending requests, to avoid the executor queue to grow indefinitely. If zero or negative, the number of pending requests is unlimited.

10000

enableBusyWait

Option to enable busy-wait settings. Default is false.
WARNING: This option will enable spin-waiting on executors and IO threads in order to reduce latency during
context switches. The spinning will consume 100% CPU even when bookie is not doing any work. It is recommended to
reduce the number of threads in the main workers pool and Netty event loop to only have few CPU cores busy.

Long poll settings

Parameter

Description

Default

requestTimerTickDurationMs

The tick duration for long poll request timer, in milliseconds. See HashedWheelTimer for more details.

10

requestTimerNumTicks

The number of ticks per wheel for long poll request timer. See HashedWheelTimer for more details.

1024

Read-only mode support

Parameter

Description

Default

readOnlyModeEnabled

If all ledger directories configured are full, then support only read requests for clients. If “readOnlyModeEnabled=true” then on all ledger disks full, bookie will be converted to read-only mode and serve only read requests. Otherwise the bookie will be shutdown. By default this will be disabled.

true

forceReadOnlyBookie

Whether the bookie is force started in read only mode or not.

false

persistBookieStatusEnabled

Persist the bookie status locally on the disks. So the bookies can keep their status upon restarts.

false

Netty server settings

Parameter

Description

Default

serverTcpNoDelay

This settings is used to enabled/disabled Nagle’s algorithm, which is a means of improving the efficiency of TCP/IP networks by reducing the number of packets that need to be sent over the network.

If you are sending many small messages, such that more than one can fit in a single IP packet, setting server.tcpnodelay to false to enable Nagle algorithm can provide better performance.

true

serverSockKeepalive

This setting is used to send keep-alive messages on connection-oriented sockets.

true

serverTcpLinger

The socket linger timeout on close. When enabled, a close or shutdown will not return until all queued messages for the socket have been successfully sent or the linger timeout has been reached. Otherwise, the call returns immediately and the closing is done in the background.

0

byteBufAllocatorSizeInitial

The Recv ByteBuf allocator initial buf size.

65536

byteBufAllocatorSizeMin

The Recv ByteBuf allocator min buf size.

65536

byteBufAllocatorSizeMax

The Recv ByteBuf allocator max buf size.

1048576

nettyMaxFrameSizeBytes

The maximum netty frame size in bytes. Any message received larger than this will be rejected.

5242880

Http server settings

Parameter

Description

Default

httpServerEnabled

The flag enables/disables starting the admin http server.

false

httpServerPort

The http server port to listen on if httpServerEnabled is set to true.

8080

Security settings

Parameter

Description

Default

bookieAuthProviderFactoryClass

The bookie authentication provider factory class name. If this is null, no authentication will take place.

permittedStartupUsers

The list of users are permitted to run the bookie process. Any users can run the bookie process if it is not set.

Example settings - “permittedStartupUsers=user1,user2,user3”

TLS settings

Parameter

Description

Default

tslProvider

TLS Provider (JDK or OpenSSL)

OpenSSL

tlsProviderFactoryClass

The path to the class that provides security.

org.apache.bookkeeper.security.SSLContextFactory

tlsClientAuthentication

Type of security used by server.

true

tlsKeyStoreType

Bookie Keystore type.

JKS

tlsKeyStore

Bookie Keystore location (path).

tlsKeyStore

Bookie Keystore location (path).

tlsKeyStorePasswordPath

Bookie Keystore password path, if the keystore is protected by a password.

tlsTrustStoreType

Bookie Truststore type.

tlsTrustStore

Bookie Truststore location (path).

tlsTrustStorePasswordPath

Bookie Truststore password path, if the truststore is protected by a password.

Journal settings

Parameter

Description

Default

journalDirectories

The directories to which Bookkeeper outputs its write-ahead log (WAL). Could define multi directories to store write head logs, separated by ‘,’.
For example:
journalDirectories=/tmp/bk-journal1,/tmp/bk-journal2
If journalDirectories is set, bookies will skip journalDirectory and use this setting directory.

/tmp/bk-journal

journalDirectory

@Deprecated since 4.5.0, in favor of using journalDirectories.

The directory to which Bookkeeper outputs its write-ahead log (WAL).

/tmp/bk-txn

journalFormatVersionToWrite

The journal format version to write.
Available formats are 1-5:
1: no header
2: a header section was added
3: ledger key was introduced
4: fencing key was introduced
5: expanding header to 512 and padding writes to align sector size configured by journalAlignmentSize
6: persisting explicitLac is introduced

By default, it is 6.
If you’d like to disable persisting ExplicitLac, you can set this config to < 6 and also fileInfoFormatVersionToWrite should be set to 0. If there is mismatch then the serverconfig is considered invalid.
You can disable padding-writes by setting journal version back to 4. This feature is available in 4.5.0 and onward versions.

6

journalMaxSizeMB

Max file size of journal file, in mega bytes. A new journal file will be created when the old one reaches the file size limitation.

2048

journalMaxBackups

Max number of old journal file to kept. Keep a number of old journal files would help data recovery in specia case.

5

journalPreAllocSizeMB

How much space should we pre-allocate at a time in the journal.

16

journalWriteBufferSizeKB

Size of the write buffers used for the journal.

64

journalRemoveFromPageCache

Should we remove pages from page cache after force write

true

journalSyncData

Should the data be fsynced on journal before acknowledgment.
By default, data sync is enabled to guarantee durability of writes. Beware - when disabling data sync in the bookie journal
might improve the bookie write performance, it will also introduce the possibility of data loss. With no fsync, the journal
entries are written in the OS page cache but not flushed to disk. In case of power failure, the affected bookie might lose
the unflushed data. If the ledger is replicated to multiple bookies, the chances of data loss are reduced though still present.

true

journalAdaptiveGroupWrites

Should we group journal force writes, which optimize group commit for higher throughput.

true

journalMaxGroupWaitMSec

Maximum latency to impose on a journal write to achieve grouping.

2

journalBufferedWritesThreshold

Maximum writes to buffer to achieve grouping.

524288

journalFlushWhenQueueEmpty

If we should flush the journal when journal queue is empty.

false

journalAlignmentSize

All the journal writes and commits should be aligned to given size. If not, zeros will be padded to align to given size.

512

journalBufferedEntriesThreshold

Maximum entries to buffer to impose on a journal write to achieve grouping.

0

journalFlushWhenQueueEmpty

If we should flush the journal when journal queue is empty.

false

journalQueueSize

Set the size of the journal queue.

10000

Ledger storage settings

Parameter

Description

Default

ledgerStorageClass

Ledger storage implementation class

Options:

org.apache.bookkeeper.bookie.InterleavedLedgerStorage

org.apache.bookkeeper.bookie.SortedLedgerStorage

org.apache.bookkeeper.bookie.storage.ldb.DbLedgerStorage

org.apache.bookkeeper.bookie.SortedLedgerStorage

sortedLedgerStorageEnabled

@Deprecated in favor of using ledgerStorageClass

Whether sorted-ledger storage enabled (default true)

true

ledgerDirectories

The directory to which Bookkeeper outputs ledger snapshots. You can define multiple directories to store snapshots separated by a comma, for example /tmp/data-dir1,/tmp/data-dir2.

/tmp/bk-data

indexDirectories

The directories in which index files are stored. If not specified, the value of ledgerDirectories will be used.

/tmp/bk-data

minUsableSizeForIndexFileCreation

Minimum safe usable size to be available in index directory for bookie to create index file while replaying journal at the time of bookie start in readonly mode (in bytes)

1073741824

minUsableSizeForEntryLogCreation

Minimum safe usable size to be available in ledger directory for bookie to create entry log files (in bytes).
This parameter allows creating entry log files when there are enough disk spaces, even when
the bookie is running at readonly mode because of the disk usage is exceeding diskUsageThreshold.
Because compaction, journal replays can still write data to disks when a bookie is readonly.

1.2 * `logSizeLimit`

minUsableSizeForHighPriorityWrites

Minimum safe usable size to be available in ledger directory for bookie to accept high priority writes even it is in readonly mode.

1.2 * `logSizeLimit`

flushInterval

When entryLogPerLedgerEnabled is enabled, checkpoint doesn’t happens when a new active entrylog is created / previous one is rolled over. Instead SyncThread checkpoints periodically with ‘flushInterval’ delay (in milliseconds) in between executions. Checkpoint flushes both ledger entryLogs and ledger index pages to disk. Flushing entrylog and index files will introduce much random disk I/O. If separating journal dir and ledger dirs each on different devices, flushing would not affect performance. But if putting journal dir and ledger dirs on same device, performance degrade significantly on too frequent flushing. You can consider increment flush interval to get better performance, but you need to pay more time on bookie server restart after failure. This config is used only when entryLogPerLedgerEnabled is enabled.

10000

allowStorageExpansion

Allow the expansion of bookie storage capacity. Newly added ledger and index directories must be empty.

false

Entry log settings

Parameter

Description

Default

logSizeLimit

Max file size of entry logger, in bytes. A new entry log file will be created when the old one reaches the file size limitation.

2147483648

entryLogFilePreallocationEnabled

Enable/Disable entry logger preallocation

true

flushEntrylogBytes

Entry log flush interval, in bytes. Setting this to 0 or less disables this feature and makes flush happen on log rotation. Flushing in smaller chunks but more frequently reduces spikes in disk I/O. Flushing too frequently may negatively affect performance.

Specifies if entryLog per ledger is enabled/disabled. If it is enabled, then there would be a active entrylog for each ledger. It would be ideal to enable this feature if the underlying storage device has multiple DiskPartitions or SSD and if in a given moment, entries of fewer number of active ledgers are written to the bookie.

entrylogMapAccessExpiryTimeInSeconds

config specifying if the entrylog per ledger is enabled, then the amount of time EntryLogManagerForEntryLogPerLedger should wait for closing the entrylog file after the last addEntry call for that ledger, if explicit writeclose for that ledger is not received.

300

maximumNumberOfActiveEntryLogs

in entryLogPerLedger feature, this specifies the maximum number of entrylogs that can be active at a given point in time. If there are more number of active entryLogs then the maximumNumberOfActiveEntryLogs then the entrylog will be evicted from the cache.

Entry log compaction settings

Parameter

Description

Default

compactionRate

The rate at which compaction will read entries. The unit is adds per second.

1000

minorCompactionThreshold

Threshold of minor compaction. For those entry log files whose remaining size percentage reaches below this threshold will be compacted in a minor compaction. If it is set to less than zero, the minor compaction is disabled.

0.2

minorCompactionInterval

Interval to run minor compaction, in seconds. If it is set to less than zero, the minor compaction is disabled.

3600

compactionMaxOutstandingRequests

Set the maximum number of entries which can be compacted without flushing. When compacting, the entries are written to the entrylog and the new offsets are cached in memory. Once the entrylog is flushed the index is updated with the new offsets. This parameter controls the number of entries added to the entrylog before a flush is forced. A higher value for this parameter means more memory will be used for offsets. Each offset consists of 3 longs. This parameter should not be modified unless you know what you’re doing.

100000

majorCompactionThreshold

Threshold of major compaction. For those entry log files whose remaining size percentage reaches below this threshold will be compacted in a major compaction. Those entry log files whose remaining size percentage is still higher than the threshold will never be compacted. If it is set to less than zero, the minor compaction is disabled.

0.8

majorCompactionInterval

Interval to run major compaction, in seconds. If it is set to less than zero, the major compaction is disabled.

86400

isThrottleByBytes

Throttle compaction by bytes or by entries.

false

compactionRateByEntries

Set the rate at which compaction will read entries. The unit is adds per second.

1000

compactionRateByBytes

Set the rate at which compaction will read entries. The unit is bytes added per second.

1000000

useTransactionalCompaction

Flag to enable/disable transactional compaction. If it is set to true, it will use transactional compaction, which uses
new entry log files to store entries after compaction; otherwise, it will use normal compaction, which shares same entry
log file with normal add operations.

false

Garbage collection settings

Parameter

Description

Default

gcWaitTime

How long the interval to trigger next garbage collection, in milliseconds. Since garbage collection is running in background, too frequent gc will heart performance. It is better to give a higher number of gc interval if there is enough disk capacity.

1000

gcOverreplicatedLedgerWaitTime

How long the interval to trigger next garbage collection of overreplicated ledgers, in milliseconds. This should not be run very frequently since we read the metadata for all the ledgers on the bookie from zk.

86400000

isForceGCAllowWhenNoSpace

Whether force compaction is allowed when the disk is full or almost full. Forcing GC may get some space back, but may also fill up disk space more quickly. This is because new log files are created before GC, while old garbage log files are deleted after GC.

false

verifyMetadataOnGC

Whether the bookie should double check if a ledger exists in metadata service prior to gc.

false

Disk utilization

Parameter

Description

Default

diskUsageThreshold

For each ledger dir, maximum disk space which can be used. Default is 0.95f. i.e. 95% of disk can be used at most after which nothing will be written to that partition. If all ledger dir partions are full, then bookie will turn to readonly mode if ‘readOnlyModeEnabled=true’ is set, else it will shutdown. Valid values should be in between 0 and 1 (exclusive).

0.95

diskUsageWarnThreshold

The disk free space low water mark threshold. Disk is considered full when usage threshold is exceeded. Disk returns back to non-full state when usage is below low water mark threshold. This prevents it from going back and forth between these states frequently when concurrent writes and compaction are happening. This also prevent bookie from switching frequently between read-only and read-writes states in the same cases.

0.95

diskUsageLwmThreshold

Set the disk free space low water mark threshold. Disk is considered full when usage threshold is exceeded. Disk returns back to non-full state when usage is below low water mark threshold. This prevents it from going back and forth between these states frequently when concurrent writes and compaction are happening. This also prevent bookie from switching frequently between read-only and read-writes states in the same cases.

Sorted Ledger Storage Settings

The number of bytes we should use as chunk allocation for org.apache.bookkeeper.bookie.SkipListArena

4194304

skipListArenaMaxAllocSize

The max size we should allocate from the skiplist arena. Allocations larger than this should be allocated directly by the VM to avoid fragmentation.

131072

openFileLimit

Max number of ledger index files could be opened in bookie server. If number of ledger index files reaches this limitation, bookie server started to swap some ledgers from memory to disk. Too frequent swap will affect performance. You can tune this number to gain performance according your requirements.

20000

fileInfoCacheInitialCapacity

The minimum total size of the internal file info cache table. Providing a large enough estimate at construction time avoids the need for expensive resizing operations later,
but setting this value unnecessarily high wastes memory. The default value is 1/4 of openFileLimit if openFileLimit is positive, otherwise it is 64.

fileInfoMaxIdleTime

The max idle time allowed for an open file info existed in the file info cache. If the file info is idle for a long time, exceed the given time period. The file info will be
evicted and closed. If the value is zero or negative, the file info is evicted only when opened files reached openFileLimit.

0

fileInfoFormatVersionToWrite

The fileinfo format version to write.
Available formats are 0-1:
0: Initial version
1: persisting explicitLac is introduced

By default, it is 1. If you’d like to disable persisting ExplicitLac, you can set this config to 0 and also journalFormatVersionToWrite should be set to < 6. If there is mismatch then the serverconfig is considered invalid.

1

pageSize

Size of a index page in ledger cache, in bytes. A larger index page can improve performance writing page to disk, which is efficent when you have small number of ledgers and these ledgers have similar number of entries. If you have large number of ledgers and each ledger has fewer entries, smaller index page would improve memory usage.

8192

pageLimit

How many index pages provided in ledger cache. If number of index pages reaches this limitation, bookie server starts to swap some ledgers from memory to disk. You can increment this value when you found swap became more frequent. But make sure pageLimit*pageSize should not more than JVM max memory limitation, otherwise you would got OutOfMemoryException. In general, incrementing pageLimit, using smaller index page would gain bettern performance in lager number of ledgers with fewer entries case. If pageLimit is -1, bookie server will use 1/3 of JVM memory to compute the limitation of number of index pages.

-1

numOfMemtableFlushThreads

When entryLogPerLedger is enabled SortedLedgerStorage flushes entries from memTable using OrderedExecutor having numOfMemtableFlushThreads number of threads.

8

DB Ledger Storage Settings

Parameter

Description

Default

dbStorage_writeCacheMaxSizeMb

Size of write cache. Memory is allocated from JVM direct memory. Write cache is used for buffer entries before flushing into the entry log. For good performance, it should be big enough to hold a sub.

Size of RocksDB block-cache. RocksDB is used for storing ledger indexes.
For best performance, this cache should be big enough to hold a significant portion of the index database which can reach ~2GB in some cases.

268435456

dbStorage_rocksDB_writeBufferSizeMB

Size of RocksDB write buffer. RocksDB is used for storing ledger indexes.

64

dbStorage_rocksDB_sstSizeInMB

Size of RocksDB sst file size in MB. RocksDB is used for storing ledger indexes.

64

dbStorage_rocksDB_blockSize

65536

dbStorage_rocksDB_bloomFilterBitsPerKey

10

dbStorage_rocksDB_numLevels

-1

dbStorage_rocksDB_numFilesInLevel0

10

dbStorage_rocksDB_maxSizeInLevel1MB

256

Metadata Service Settings

Parameter

Description

Default

metadataServiceUri

metadata service uri that bookkeeper is used for loading corresponding metadata driver and resolving its metadata service location.

zk+hierarchical://localhost:2181/ledgers

ledgerManagerFactoryClass

@Deprecated in favor of using metadataServiceUri

The ledger manager factory class, which defines how ledgers are stored, managed, and garbage collected. See the Ledger Manager guide for more details.

hierarchical

allowShadedLedgerManagerFactoryClass

Sometimes the bookkeeper server classes are shaded. The ledger manager factory classes might be relocated to be under other packages.
This would fail the clients using shaded factory classes since the factory classes are stored in cookies and used for verification.
Users can enable this flag to allow using shaded ledger manager factory classes to connect to a bookkeeper cluster.

false

shadedLedgerManagerFactoryClassPrefix

The shaded ledger manager factory prefix. This is used when allowShadedLedgerManagerFactoryClass is set to true.

dlshade.

ZooKeeper Metadata Service Settings

Parameter

Description

Default

zkLedgersRootPath

@Deprecated in favor of using metadataServiceUri

Root Zookeeper path to store ledger metadata. This parameter is used by zookeeper-based ledger manager as a root znode to store all ledgers.

/ledgers

zkServers

@Deprecated in favor of using metadataServiceUri

A list of one of more servers on which Zookeeper is running. The server list can be comma separated values, for example zkServers=zk1:2181,zk2:2181,zk3:2181.

localhost:2181

zkTimeout

ZooKeeper client session timeout in milliseconds. Bookie server will exit if it received SESSION_EXPIRED because it was partitioned off from ZooKeeper for more than the session timeout JVM garbage collection, disk I/O will cause SESSION_EXPIRED. Increment this value could help avoiding this issue.

10000

zkRetryBackoffStartMs

The Zookeeper client backoff retry start time in millis.

1000

zkRetryBackoffMaxMs

The Zookeeper client backoff retry max time in millis.

10000

zkRequestRateLimit

The Zookeeper request limit. It is only enabled when setting a postivie value.

0

zkEnableSecurity

Set ACLs on every node written on ZooKeeper, this way only allowed users will be able to read and write BookKeeper metadata stored on ZooKeeper. In order to make ACLs work you need to setup ZooKeeper JAAS authentication all the bookies and Client need to share the same user, and this is usually done using Kerberos authentication. See ZooKeeper documentation

the directory for reporting stats in csv format. see csv reporter for more details.

null

codahaleStatsSlf4jEndpoint

the slf4j endpoint for reporting stats. see slf4j reporter for more details.

null

codahaleStatsJmxEndpoint

the jmx endpoint for reporting stats. see jmx reporter for more details.

Twitter Ostrich Metrics Provider

Parameter

Description

Default

statsExport

Flag to control whether to expose ostrich metrics via a http endpoint configured by statsHttpPort.

false

statsHttpPort

The http port of exposing ostrich stats if statsExport is set to true

9002

Twitter Science Metrics Provider

Parameter

Description

Default

statsExport

Flag to control whether to expose metrics via a http endpoint configured by statsHttpPort.

false

statsHttpPort

The http port of exposing stats if statsExport is set to true

9002

AutoRecovery general settings

Parameter

Description

Default

autoRecoveryDaemonEnabled

Whether the bookie itself can start auto-recovery service also or not.

digestType

The default digest type used for opening ledgers.

CRC32

passwd

The default password used for opening ledgers. Default value is empty string.

enableDigestTypeAutodetection

The flag to enable/disable digest type auto-detection. If it is enabled, the bookkeeper client will ignore the provided digest type provided at digestType and the provided passwd provided at passwd.

true

AutoRecovery placement settings

Parameter

Description

Default

ensemblePlacementPolicy

The ensemble placement policy used for finding bookie for re-replicating entries.

Options:

org.apache.bookkeeper.client.RackawareEnsemblePlacementPolicy

org.apache.bookkeeper.client.RegionAwareEnsemblePlacementPolicy

org.apache.bookkeeper.client.RackawareEnsemblePlacementPolicy

reppDnsResolverClass

The DNS resolver class used for resolving network locations for bookies. The setting is used
when using either RackawareEnsemblePlacementPolicy and RegionAwareEnsemblePlacementPolicy.

org.apache.bookkeeper.net.ScriptBasedMapping

networkTopologyScriptFileName

The bash script used by ScriptBasedMapping DNS resolver for resolving bookies’ network locations.

networkTopologyScriptNumberArgs

The max number of args used in the script provided at networkTopologyScriptFileName.

minNumRacksPerWriteQuorum

minimum number of racks per write quorum. RackawareEnsemblePlacementPolicy will try to get bookies from atleast ‘minNumRacksPerWriteQuorum’ racks for a writeQuorum.

enforceMinNumRacksPerWriteQuorum

‘enforceMinNumRacksPerWriteQuorum’ enforces RackawareEnsemblePlacementPolicy to pick bookies from ‘minNumRacksPerWriteQuorum’ racks for a writeQuorum. If it cann’t find bookie then it would throw BKNotEnoughBookiesException instead of picking random one.

ignoreLocalNodeInPlacementPolicy

‘ignoreLocalNodeInPlacementPolicy’ specifies whether to ignore localnode in the internal logic of placement policy. If it is not possible or useful to use Bookkeeper client node’s (or AutoReplicator) rack/region info. for placement policy then it is better to ignore localnode instead of false alarming with log lines and metrics.

AutoRecovery auditor settings

Parameter

Description

Default

auditorPeriodicBookieCheckInterval

The time interval between auditor bookie checks, in seconds. The auditor bookie check checks ledger metadata to see which bookies should contain entries for each ledger. If a bookie that should contain entries is unavailable, then the ledger containing that entry is marked for recovery. Setting this to 0 disables the periodic check. Bookie checks will still run when a bookie fails. The default is once per day.

86400

auditorPeriodicCheckInterval

The time interval, in seconds, at which the auditor will check all ledgers in the cluster. By default this runs once a week.

Set this to 0 to disable the periodic check completely. Note that periodic checking will put extra load on the cluster, so it should not be run more frequently than once a day.

604800

auditorPeriodicPlacementPolicyCheckInterval

The time interval between auditor placement policy checks, in seconds. The auditor placement policy check validates if the ensemble of segments of all the closed ledgers is adhering to the placement policy. It is just monitoring scrutiny but doesn’t take any corrective measure other than logging error and reporting metrics. By default it is disabled.

0

auditorLedgerVerificationPercentage

The percentage of a ledger (fragment)’s entries will be verified before claiming a fragment as missing. If it is 0, it only verifies the first and last entries of a given fragment.

0

lostBookieRecoveryDelay

How long to wait, in seconds, before starting autorecovery of a lost bookie.

0

storeSystemTimeAsLedgerUnderreplicatedMarkTime

Enable the Auditor to use system time as underreplicated ledger mark time. If this is enabled, Auditor will write a ctime field into the underreplicated ledger znode.

true

AutoRecovery replication worker settings

Parameter

Description

Default

rereplicationEntryBatchSize

The number of entries that a replication will rereplicate in parallel.

10

openLedgerRereplicationGracePeriod

The grace period, in seconds, that the replication worker waits before fencing and replicating a ledger fragment that’s still being written to upon bookie failure.

30

lockReleaseOfFailedLedgerGracePeriod

the grace period so that if the replication worker fails to replicate a underreplicatedledger for more than ReplicationWorker.MAXNUMBER_REPLICATION_FAILURES_ALLOWED_BEFORE_DEFERRING number of times, then instead of releasing the lock immediately after failed attempt, it will hold under replicated ledger lock for this grace period and then it will release the lock.

60

rwRereplicateBackoffMs

The time to backoff when replication worker encounters exceptions on replicating a ledger, in milliseconds.

5000

Memory allocator settings

Parameter

Description

Default

allocatorPoolingPolicy

Define the memory pooling policy.

Available options are:

PooledDirect: Use Direct memory for all buffers and pool the memory.
Direct memory will avoid the overhead of JVM GC and most
memory copies when reading and writing to socket channel.
Pooling will add memory space overhead due to the fact that
there will be fragmentation in the allocator and that threads
will keep a portion of memory as thread-local to avoid
contention when possible.

UnpooledHeap: Allocate memory from JVM heap without any pooling.
This option has the least overhead in terms of memory usage
since the memory will be automatically reclaimed by the
JVM GC but might impose a performance penalty at high
throughput.

PooledDirect

allocatorPoolingConcurrency

Controls the amount of concurrency for the memory pool.
Default is to have a number of allocator arenas equals to 2 * CPUS.
Decreasing this number will reduce the amount of memory overhead, at the
expense of increased allocation contention.

2 * CPUS

allocatorOutOfMemoryPolicy

Define the memory allocator out of memory policy.

Available options are:

FallbackToHeap: If it’s not possible to allocate a buffer from direct memory,
fallback to allocate an unpooled buffer from JVM heap.
This will help absorb memory allocation spikes because the heap
allocations will naturally slow down the process and will result
if full GC cleanup if the Heap itself is full.